The present invention is directed, in general, to a pump, and, more specifically, to a miniature pump used to move a liquid and that is powered by a micro-motor.
The increased emphasis on miniaturization in industries such as electronics and medicine has created a demand for miniaturization of several devices that would otherwise become obsolete solely for reasons of size. For example, a traditional method of containing temperature build-up in electronic circuitry is to associate an active cooling device, such as a fan, with a printed wiring or circuit board. The fan moves cooling air over the circuitry and thereby increases the rate of thermal transfer from the circuitry to the surrounding ambient environment. A small fan is conventionally used in this fashion to cool a computer motherboard. The same fan, however, is rendered obsolete when more compact electronic circuits and devices require cooling. This is why smaller, and even miniature, fans have been developed for cooling smaller electronic circuits and components.
As a general rule, the most efficient heat control takes place when a heat-generating circuit or component is directly associated with a heat transfer device. Prior art finned heat sinks, for example, frequently have one or more heat generating components directly attached to the heat sink itself. This configuration permits the heat sink to absorb heat directly from the component or circuit and transfer the heat to the surrounding ambient air.
Although traditional passive heat control methods, such as heat sinks, have been successfully employed to cool compact electronic devices, in some cases the problems associated with temperature control have become so pronounced that passive devices are no longer sufficient. This is particularly true for electronic circuits that are small and complex. The circuit complexity results in a larger number of more powerful circuit components that generate large amounts of heat, the removal of which is further complicated by the reduced size of the electronics system. In some instances, not only does the classic finned heat sink not provide the requisite level of temperature control, but some active cooling devices, such as fans, are also inadequate. In such cases even more aggressive heat control measures must be taken. One such aggressive technique is to circulate a coolant fluid to gather heat and transfer it to a place where it can be radiated into the surrounding ambient air. The use of a liquid coolant to provide heat control for smaller electronic circuits and devices has its own set of problems. One such problem is keeping the liquid coolant moving through a predetermined cooling path.
Accordingly, what is needed in the art is a miniature pump that can be used to move useful quantities of liquid and that can be associated with active cooling devices used to provide temperature control for small electronic components and circuits.
To address the above-discussed deficiencies of the prior art, the present invention provides a miniature liquid transfer pump. The pump has a housing that includes first and second blocks joinable to form a leak-resistant impeller chamber with a drive shaft aperture, an inlet and an outlet. An impeller is located in the impeller chamber and a micro-motor with a drive shaft extending therefrom is mounted to the housing. The drive shaft on the micro-motor passes through the drive shaft aperture and engages the impeller. The micro-motor drives the impeller to draw liquid through the inlet and eject the liquid through the outlet.
The present invention therefore, in broad scope, introduces a miniature pump useful for moving liquids from a source to a destination in environments where larger pumps cannot be used for one reason or another. For example, prior art pumps are, in most cases, not suitable for moving liquid coolant when used as an active heat transfer device for cooling electronic equipment in a confined space. The invention provides for a pump that can be used in such an environment. Such a pump is also useful, for example, in moving liquid medicines in a hospital environment and in moving certain chemicals in a manufacturing environment.
In one embodiment of the pump, the impeller has a vane with a notch thereon, which embodiment is illustrated and described in more detail herein. This aspect of the invention is particularly beneficial because the pump can move greater quantities of liquid than it could otherwise move were the notch not present. In another embodiment, the pump uses an impeller with a flat vane. In another particularly useful embodiment of the invention, a sealing plate is located on the impeller, transversely oriented to the rotational axis of the impeller, to improve the leak-resistant characteristics of the impeller chamber.
In still another embodiment, the pump has a mounting plate with a mounting plate aperture therein. The mounting plate is coupled to the housing adjacent to the micro-motor so that the drive shaft on the micro-motor passes through the mounting plate aperture before passing through the drive shaft aperture of the impeller chamber.
Another embodiment of the invention, provides for an alignment feature to be located on the surface of one of the first and second blocks that is joinable to the surface of the other block which has an alignment feature receptacle. In one aspect of the invention, the pump has a clip securing the first and second blocks together.
To buffer the flow of fluid through the pump, a particularly useful embodiment of the invention provides for the inlet to have a fluid reservoir coupled to it. Another aspect of this embodiment provides for a clip to secure the reservoir to the housing. In still another embodiment of the invention, the housing of the pump has a block shape. In one aspect of this embodiment, each side of the block shape has a dimension of less than about one inch.
Other embodiments of the invention include methods of manufacturing a miniature liquid transfer pump. In one embodiment, the method comprises forming a housing that includes first and second blocks joinable to form a leak-resistant impeller chamber having a drive shaft aperture, an inlet and an outlet. An impeller is formed and located in the impeller chamber. A micro-motor with a drive shaft extending therefrom is mounted to the housing such that the drive shaft passes through the drive shaft aperture and engages and drives the impeller to draw liquid through the inlet and eject it through the outlet.
Yet another aspect of the invention provides for a liquid transfer device for transporting a liquid from one location to another. In one embodiment, a liquid transfer device comprises a pipe with a source end and a destination end with a miniature liquid transfer pump coupled to the pipe to move liquid through the pipe.
The foregoing has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.